Biomass is biological material which may be derived from recently living organisms including plant and animal material. Examples of materials from which biomass can be derived are wood from forests, material left over from agricultural and forestry processes, and organic wastes derived from humans, industrial processes and animals. Biomass may be used as a renewable source of fuel to produce heat or electricity. The composition of biomass is largely carbon, hydrogen and oxygen. Biomass may also be employed as a feedstock for other fuels, including the production of syngas, via its pyrolysis.
Pyrolysis is the thermochemical decomposition of organic material at elevated temperatures. Pyrolysis should occur in an atmosphere absent of oxygen (or reactive gas) to ensure that the organic material does not undergo combustion. At these elevated temperatures and in the absence of oxygen the organic material undergoes a chemical decomposition to form syngas and the by-product, biochar. Biochar can be used to generate energy or can, alternatively, be used as a soil amendment agent. Another useful characteristic of the pyrolysis of organic material is that potential greenhouse emissions remain in the solid state (biochar) and are therefore not released into the atmosphere, making it a more environmentally friendly process.
A problem currently encountered in pyrolysis is that dust, oils and tars are often present in the generated syngas. As a result, the syngas will need to be purified before it can be used. Another problem associated with large scale pyrolysis is that it is difficult to continuously pyrolyze biomass. Many pyrolysis systems are sequential systems, whereby biomass is loaded into a chamber, pyrolysis is initiated, syngas is generated and the chamber opened to remove the biochar before a new biomass load can then be added. Disadvantages to this system include syngas being lost when the chamber is opened, the time required for reloading the chamber and the poor energy efficiency due to frequent cooling and ramping up of heat.
Furthermore, biomass with high moisture content can be difficult to pyrolyze because additional heat energy is required to remove the moisture before pyrolysis can occur. As such, high moisture content biomass is required to be separately dried or treated prior to introduction to the pyrolysis chamber. Due to this requirement, many high moisture content biomasses are overlooked for use in pyrolysis when low moisture content biomass is accessible. Due to this, many types of biomass are overlooked as possible fuel sources and their energy value is not realised.
It would be advantageous to provide for a pyrolysis apparatus and method of use thereof that addresses one or more of these drawbacks or provides a useful commercial alternative.